Concrete mix pouring sequence for uniform setting and curing of bridge decks

Abstract

Concrete bridge decks are cast in segments using multiple mix batches in a process that can extend up to an entire working day. Construction codes state that the initial concrete must stay plastic over the entire casting operation, however this requirement is practically impossible to achieve with regular casting and curing procedures. This paper reports the experimental evaluation of the performance of a suggested pouring sequence of class K concrete designed for bridge decks, where retarding and accelerating admixtures were used to achieve homogeneous thermo-mechanical concrete properties based on uniform setting and curing at early age. The proposed pouring sequence was investigated in both laboratory conditions as well as in outdoors environment. In order to optimize the resulting properties, the effects of different curing methods were investigated. Taking into consideration variation in environmental conditions at a regular construction season of late spring and summer in West Virginia, the suggested sequence was able to achieve uniform setting times as well as thermal properties while being placed along an entire working day.